/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.xiongyingqi.util;

import java.io.File;
import java.io.IOException;

/**
 * Utility methods for working with the file system.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 2.5.3
 */
public abstract class FileSystemUtils {

    /**
     * Delete the supplied {@link java.io.File} - for directories,
     * recursively delete any nested directories or files as well.
     *
     * @param root the root {@code File} to delete
     * @return {@code true} if the {@code File} was deleted,
     * otherwise {@code false}
     */
    public static boolean deleteRecursively(File root) {
        if (root != null && root.exists()) {
            if (root.isDirectory()) {
                File[] children = root.listFiles();
                if (children != null) {
                    for (File child : children) {
                        deleteRecursively(child);
                    }
                }
            }
            return root.delete();
        }
        return false;
    }

    /**
     * Recursively copy the contents of the {@code src} file/directory
     * to the {@code dest} file/directory.
     *
     * @param src  the source directory
     * @param dest the destination directory
     * @throws java.io.IOException in the case of I/O errors
     */
    public static void copyRecursively(File src, File dest) throws IOException {
        org.springframework.util.Assert.isTrue(src != null && (src.isDirectory() || src.isFile()), "Source File must denote a directory or file");
        org.springframework.util.Assert.notNull(dest, "Destination File must not be null");
        doCopyRecursively(src, dest);
    }

    /**
     * Actually copy the contents of the {@code src} file/directory
     * to the {@code dest} file/directory.
     *
     * @param src  the source directory
     * @param dest the destination directory
     * @throws java.io.IOException in the case of I/O errors
     */
    private static void doCopyRecursively(File src, File dest) throws IOException {
        if (src.isDirectory()) {
            dest.mkdir();
            File[] entries = src.listFiles();
            if (entries == null) {
                throw new IOException("Could not list files in directory: " + src);
            }
            for (File entry : entries) {
                doCopyRecursively(entry, new File(dest, entry.getName()));
            }
        } else if (src.isFile()) {
            try {
                dest.createNewFile();
            } catch (IOException ex) {
                IOException ioex = new IOException("Failed to create file: " + dest);
                ioex.initCause(ex);
                throw ioex;
            }
            FileCopyUtils.copy(src, dest);
        } else {
            // Special File handle: neither a file not a directory.
            // Simply skip it when contained in nested directory...
        }
    }

}
